When asked about it today, Addante would say only, "There are rumors all over the place. All I can tell you is that we have companies who are partners or customers and Yahoo happens to be both."

Separately, however, a source tells us that the deal is not happening.

In fact, Rubicon is behaving like a company that does not intend to be acquired. It beefed up its management today with two appointments and Addante says he's looking to spend some of his company's cash to make acquisitions.

Tappin replaces Brian Barnum as CFO, who exited Rubicon after only a year on the job. Addante didn't address that issue. We're told separately that Rubicon simply wanted to take advantage of the availability of Tappin.

He did say that Rubicon has reached a size where it needs more management — 250 employees. Tappin has experience with both M&A and taking companies public.

In terms of acquisitions, Addante said mobile, video, data analytics, international and order automation were hot areas for the company. "We're looking across the board," he said.

Compared to last September, Addante sounded a little less enthusiastic about the idea of going public with an IPO. Then he told us he was considering an IPO. Today, however, he says. "I can't comment specifically on IPO plans," he says. We continue to grow aggressively."